1. Urinary system

2. General outline component urinary organs: kidneys
micturition organs: ureter, bladder and urethra
function
discharge metabolite
regulate the balance of water and electrolyte
endocrine function: renin, erythropoietin,
prostaglandin

3. Renal anatomic structure
Fibrosa
Cortical labyrinth
Medullary ray
Cortex
Parenchyma
Renal pyramids
Renal columns
Medulla

4. Renal histological structure
Glomerulus
Bowman’s capsule
Renal corpuscles
nephron
Renal tubules
collecting duct
juxtaglomerular apparatus

7. Kidney

8. Renal cortex
Renal medulla

9. Structure of Renal corpuscle:
afferent arteriole
efferent arteriole
capillary network
mesangial cells
Glomerulus
parietal layer: simple squamous Epi.
Bowman’s capsule
capsular cavity: filtrate
visceral layer: podocytes
(primary and secondary processes, slit membrane)

10. Renal corpuscle

12. Podocyte

13. Glomerulus
Renal corpuscle

14. Functions of Renal corpuscle:
Produce filtrate (primary urine)
fenestrated endothelium
basement membrane
slit membrane of podocyte
Filtration membrane
(filtration barrier)
molecular weight
charges
relevant factors of filtrate

15. Filtration membrane

16. Renal tubules: convoluted tubule straight tubule proximal thin segment
Henle’s loops
straight tubule
convoluted tubule
distal

18. Proximal tubule Location: cortical labyrinth
LM: simple cuboidal or pyramid Epi.
acidophilic cytoplasm
no discrete cell margin;
brush border;
longitudinal striation

19. Convoluted segments of proximal and distal tubules

20. EM: apical canaliculi and vesicles
numerous lysosomes, Mi.
many lateral interdigitations
microvilli on the surface
membrane invaginations
abundant Na+-K+ATPase

22. Function
reabsorb water, glucose, amino acid,
protein, vitamin and inorganic salts etc.
secrete ammonia and some metabolic
substances

23. thin segment location: medullary ray and renal pyramids
LM: simple squamous Epi.; pale cytoplasm,
EM: a few microvilli; less organelles
Function: water, and ions pass through easily

24. Thin segment and straight segment of distal tubule

25. Distal tubule location: medullay ray and renal pyramids
LM: simple cuboidal Epi;
clear cell boundary;
pale cytoplasm;
nuclei near lumen;
without brush border;
have longitudinal striation

26. EM: a few microvilli;
many membrane invagination;
many mitochondria;
abundant Na+-K+ATPase
Function: reabsorb Na+ and water;
excrete K+; secrete NH3

27. Distal straight tubules and collecting tubules

28. Convoluted segments of proximal and distal tubule

29. Collecting tubules: location: medullary ray and renal pyramids
components: arched collecting tubules;
straight collecting tubules;
papillary ducts
simple cuboidal Epi simple columnar Epi.,
papillary ducts line tall columnar Epi;
pale staining; distinct borders;
rare microvilli and Mi.
function: similar to that of distal convoluted
tubules

30. Straight segment of distal tubule and collecting tubule

31. Juxtaglomerular apparatus:
located in a triangle area at the vascular pole of the renal corpuscles
consist of juxtaglomerular cells, macular densa
and extraglomerular mesangial (polar cushion)
cells
function: control water and electrolyte balance;
regulate blood pressure;
produce erythropoietin

32. Juxtaglom-erular apparatus

33. Juxtaglomerular cells
smooth muscle cells of the afferent arteriole
transform into the epithelial cells
cytoplasm: a few myofibrils;
PAS-positive granules contained renin;
abundant RER, ribosomes and
well developed Golgi apparatus;
function: secrete renin and erythropoietin

34. Juxtaglomerular cell

35. Macular densa transformed from the cells of distal tubule
which near the vascular pole of the renal corpuscle
the cells become taller and narrow, arranged
compactly; pale cytoplasm; nuclei located at the
apex
a chemical (Na+ ) sensor

36. Macular densa

37. Extraglomerular mesangial cells
resemble the intraglomerular mesangial cells
gap junctions between the component of the
juxtaglomerular apparatus
transmit information

38. Features of renal blood circulation
blood flow is large
two sets of capillary network
the diameter of afferent arterioles is larger
than that of efferent, so as to facilitate filtration
the vasa recta are parallel to the Henle’s loop, so
aid water reabsorption and urine concentration

39. Blood vessels of kidney

40. Micturition organs (ureter, bladder,) Epi: transitional Epi
Lamina propria: L.C.T.
mucosa
muscle layer: smooth muscle
adventitia: fibrosa
serosa

41. Bladder

42. Ureter